PROVIDENCE — Vice President Joseph Biden and several top members of the Obama administration on Friday canceled plans to visit Providence to attend next weekend’s annual U.S. Conference of Mayors to avoid crossing a labor union picket line by the city’s firefighters union.

White House Press Secretary Robert Gibbs said in a statement that The International Association of Fire Fighters had asked –– and the administration agreed –– to “respect the picket” planned by Providence Fire Fighters Local 799. While the administration is “taking no position” in the dispute, the statement read, it has “always respected picket lines and Administration officials will not cross this one.”

The Obama administration’s cancellation is a huge blow to Mayor David N. Cicilline, who as a member of the conference’s advisory board had lobbied to bring the conference to Providence for the first time and was eager to show off his city before a national audience.

It comes just a week before about 1,200 people from around the country, including 180 mayors and their families, are to arrive in downtown to share ideas with government experts and industry leaders and hobnob with politicians. Among the Obama administration guests who will not be attending now are Attorney General Eric Holder and several cabinet members.

“I’m disappointed we won’t have the opportunity to meet with members of the administration,” Mayor Cicilline said after reading from a prepared statement at City Hall news conference. “I’m disappointed they won’t be here.”

However, he said repeatedly that he would not “cave in” to pressure from Providence Fire Fighters Local 799, whose leaders he said were “holding Providence hostage” to force him to agree to demands that he says would be harmful to taxpayers.

Paul A. Doughty, president of the city local, said he told the mayor “a year ago” of plans to picket the event.

City police union officials said on Friday that they, too, have decided to picket the conference to protest their own, separate contract dispute with the mayor.

No clear explanation was given from any of those involved for the timing of the Obama administration’s decision to cancel its trip here. The labor contract fight between the Providence mayor and the firefighters union has been going on for nearly a decade, before Cicilline took office. The two sides have been engaged in binding arbitration. When he took office, Cicilline said, the city had about 10 years of unresolved contracts; so far, 6 of those years have been resolved.

Asked whether he’d anticipated the pickets, Cicilline said that he’d “expected” the union to picket the evening events where he was scheduled to speak.

“I didn’t expect picketing,” he said, “at the annual events of the United Conference of Mayors.”

Doughty, the firefighters’ union president, said that he told Cicilline in June 2008 that his members would picket the mayors conference; the following March, the union notified the Rhode Island Congressional Delegation of its plans. Two weeks ago, Doughty said, the International Association of Fire Fighters told the Obama administration about the pickets. He said the Obama administration suggested a compromise: What if the Providence mayor stayed away from the conference? Would they agree not to picket?

Doughty said that he would call off the pickets if the mayor stayed away, but that the mayor declined to do so.

The conference attracts mayors from the nation’s largest metropolitan areas –– including Los Angeles, Chicago, Philadelphia, Dallas and Seattle –– to small towns in Arkansas, Idaho and North Dakota.

This year, the meeting’s focus is on what impact President Obama’s economic stimulus plan, the American Recovery and Reinvestment Act, is having on cities and how city executives can prepare for the next phases of the plan.

Among the top Obama administration officials who had planned to speak at the conference were Shaun Donovan, secretary of Housing and Urban Development, Commerce Secretary Gary Locke, Labor Secretary Hilda L. Solis, Attorney General Eric Holder, EPA Administrator Lisa Jackson and Senior White House Advisor Valerie Jarrett.

Donovan had been scheduled to give an address next Sunday; Biden had been scheduled to give an address the following Monday.

Cicilline had said he’d hoped that some would be available to meet with mayors more informally during the conference.

“It’s a real opportunity for them to talk to us,” he’d said before the administration canceled.

It remains to be seen whether the picket line could also deter others from attending the conference. The guests include mayors from cities such as Las Vegas and Chicago, where organized labor remains a powerful force. Las Vegas Mayor Oscar Goodman, a Democrat, is still planning to attend the conference, a spokesman, Jace Radky, said Friday night.

Chicago Mayor Richard J. Daly’s plans could not be confirmed, though a spokesman said he was unaware of the pickets.

Among the issues that will be addressed during the conference, which runs Friday through Monday at the Rhode Island Convention Center, are the nation’s economic and foreclosure crises, energy and “green” technology, new strategies to fight crime and how to improve education.

Across the nation, cities are grappling with budget shortfalls caused by losses in state aid and decreased municipal revenue. In many places, hard-fought gains made in recent years are threatened by the proliferation of foreclosed and boarded-up homes, rising unemployment, and increased crime.

As cities’ coffers dry up, the demands on municipal government services have never been greater.

Miami Mayor Manuel Diaz, who is president of the conference of mayors, had said that the annual meeting will take on special importance.

“Cities all across the country are facing challenges and many will be forced to make significant budget cuts. During the meeting, mayors will be able to share ideas and possible solutions for these challenges,” he said.

Union disputes have threatened other national gatherings. In 2004, Boston firefighters threatened to picket the Democratic National Convention in that city, raising questions whether the party’s presidential nominee, John Kerry, would cross the picket line. The picketing was averted by a last-minute contract agreement.

In 2007, Cicilline resigned as cochairman of Hillary Clinton’s Rhode Island presidential campaign rather than face firefighter and police pickets at Clinton fundraisers.

––With reports by Journal Washington bureau chief John E. Mulligan and Philip Marcelo

larditi@projo.com